Open Item: pg_controldata - machine readable?

There is an open item "pg_controldata - machine readable?" in the list:
http://wiki.postgresql.org/wiki/PostgreSQL_9.0_Open_Items

The proposal by Joe Conway is adding a new contib module.
http://archives.postgresql.org/message-id/4B959D7A.6010907@joeconway.com
http://github.com/jconway/pg_controldata

Should we add the module to 9.0? If we do so, SGML documentation is required.

IMHO, I'd like to put the feature into the core instead of a contrib
module, but we cannot change the catalog version in this time.
So, how about providing control file information through pg_settings
view? We will retrieve those variables as GUC options.

Regards,
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Takahiro Itagaki
NTT Open Source Software Center